The Behavioral Assessment/Clinical Diagnosis Core will be responsible for ensuring that a common set of age appropriate, self-report and behavioral measures are used in all four projects that employ human subjects. The aims of Project 4, Study A, and Project 5 are highly complementary; thus, they employ the same protocol for the home visits done at the early adolescent age period. The Core describes this multi-source, multi-method protocol in some detail. Areas of emphasis include Child Emotional Reactivity and Regulation (temperament); Child Mental Health; Child Attributional Styles (and other social cognitive measures; Child Cognitive Functioning (field tests); Family Characteristics; Peer Characteristics; Parental Mental Health; and Major Life Events and Daily Hassles. With our consultant, Dr. Dahl, the Core will conduct assessments of pubertal timing and also coordinate assessments (e.g., of basal and reactive cortisol in the home) with the Biological Core. In addition to this early adolescent protocol, the Core will process questionnaires and ensure high-quality coding of behavior from videotapes for younger children (7-8 years old) who participate in two twin studies described in Project 4. These assessments generate extensive videotaped records that must be objectively coded. This core will also conduct diagnostic interviews by licensed clinicians on select groups of participants, thus confirming diagnoses made in the field and benefiting Projects 1, 3, 4, and 5. Finally, with our consultant Dr. Kraemer, the Core will publish methodological papers on two topics: (1) Clarifyiing the relationship between categorical field diagnoses of child psychopathology with the DISC and prior and concurrent dimensional symptom scores from the Health and Behavior Questionnaire using Receiver Operating Characteristic (ROC) approaches. Many developmental factors will be incorporated into these analyses. (2) Examining the psychometric quality of the batteries of videotaped measures of emotion reactivity and regulation (temperament), using item analytic and structural modeling approaches. These latter measures capture key risk factors for internalizing behavioral problems.